[Azred]

There are only so many high-level abilities (HLAs) that mages may obtain; once the limit is reached that is the end. Comet, Dragon's Breath, and Energy Blades are spells; once learned, you may memorize as many of them as you have 9-th level spell slots. Isn't one extra 6th, 7th, and 8th level spell enough? Combine the extra spell slots with the Ring of Acuity, the Ring of Wizardy and, if you can get it, the Circlet of Netheril (a ToB item that I won't tell you how to get) then you will have plenty of spell slots available.